species diversity

1. Species DiversitySpecies Diversity

2. SPECIES DIVERSITYSPECIES DIVERSITY
 Species diversitySpecies diversity
– the number and– the number and
abundance ofabundance of
species presentspecies present
indifferentindifferent
communitiescommunities

3. SPECIES DIVERSITYSPECIES DIVERSITY
 Species diversity includes:Species diversity includes:

Species richnessSpecies richness – the number of different– the number of different
species in a given areaspecies in a given area

Species evennessSpecies evenness – comparative number of– comparative number of
individuals of each species presentindividuals of each species present

4. SPECIES DIVERSITYSPECIES DIVERSITY
 Diversity varies with geographical locationDiversity varies with geographical location
 The most species-rich communitiesThe most species-rich communities

Tropical rain forestsTropical rain forests

Coral reefsCoral reefs

Ocean bottom zoneOcean bottom zone

Large tropical lakesLarge tropical lakes
 Species richnessSpecies richness

Increases productivity and stability or sustainabilityIncreases productivity and stability or sustainability

Provides insurance against catastropheProvides insurance against catastrophe

5. ECOLOGICAL NICHES ANDECOLOGICAL NICHES AND
ADAPTATIONADAPTATION
 Ecological nicheEcological niche – organisms’ job or role in– organisms’ job or role in
ecosystem – everything that affects survivalecosystem – everything that affects survival
or reproductionor reproduction

Fundamental nicheFundamental niche – full potential range of– full potential range of
physical, chemical and biological conditions andphysical, chemical and biological conditions and
resources a species could theoretically useresources a species could theoretically use

Realized nicheRealized niche – the part of its fundamental– the part of its fundamental
niche that a species actually occupies to surviveniche that a species actually occupies to survive
and avoid competitionand avoid competition
 HabitatHabitat – place where organism lives– place where organism lives

6. Ecological NicheEcological Niche
 Range of toleranceRange of tolerance – range of chemical and– range of chemical and
physical conditions that must be maintainedphysical conditions that must be maintained
for a population of a species to stay alive,for a population of a species to stay alive,
grow, develop and function normallygrow, develop and function normally

7. Generalist and Specialist Species:Generalist and Specialist Species:
Broad and Narrow NichesBroad and Narrow Niches
 GeneralistGeneralist ––
species thatspecies that
tolerates a widetolerates a wide
range ofrange of
conditionsconditions
 SpecialistSpecialist ––
species thatspecies that
tolerates atolerates a
narrow range ofnarrow range of
conditionsconditions

8. Generalist vs. SpecialistGeneralist vs. Specialist
Which Makes Sense?Which Makes Sense?
 If environmental conditions are constant –If environmental conditions are constant –
specialistspecialist
 If environmental conditions change rapidly –If environmental conditions change rapidly –
generalistgeneralist

9. Specialized Feeding NichesSpecialized Feeding Niches
 Resource partitioning reduces competitionResource partitioning reduces competition
and allows sharing of limited resourcesand allows sharing of limited resources

10. SPOTLIGHTSPOTLIGHT
Cockroaches: Nature’s UltimateCockroaches: Nature’s Ultimate
SurvivorsSurvivors
 350 million years old350 million years old
 3,500 different species3,500 different species
 Ultimate generalistUltimate generalist

Can eat almost anything.Can eat almost anything.

Can live and breed almostCan live and breed almost
anywhere.anywhere.

Can withstand massiveCan withstand massive
radiation.radiation.

11. SPOTLIGHTSPOTLIGHT
The Giant Panda: A HighlyThe Giant Panda: A Highly
Endangered SpecialistEndangered Specialist
 1600 to 3000 left in the wild1600 to 3000 left in the wild
 Need bamboo = specialistNeed bamboo = specialist

Habitat currently being destroyedHabitat currently being destroyed
 Low reproductive rateLow reproductive rate

Females give birth to 1 or 2 cubsFemales give birth to 1 or 2 cubs
every 2-3 yearsevery 2-3 years

12. Species’ Roles in EcosystemsSpecies’ Roles in Ecosystems
 Native speciesNative species
 Nonnative speciesNonnative species
 Indicator speciesIndicator species
 Keystone speciesKeystone species

13. Species’ Roles in EcosystemsSpecies’ Roles in Ecosystems
 Native speciesNative species – lives in ecosystem– lives in ecosystem
 Nonnative speciesNonnative species (invasive, alien, exotic)(invasive, alien, exotic)

not native to ecosystemnot native to ecosystem

may not be harmful – crops, domesticated animalsmay not be harmful – crops, domesticated animals

can spread rapidly – no checks and balancescan spread rapidly – no checks and balances

Ex: purple loosestrife, zebra mussel, AsianEx: purple loosestrife, zebra mussel, Asian
longhorned beetlelonghorned beetle

14. Species’ Roles in EcosystemsSpecies’ Roles in Ecosystems
 Indicator speciesIndicator species – provide early warning of– provide early warning of
damage to a communitydamage to a community

biological smoke alarmbiological smoke alarm

can monitor environmental qualitycan monitor environmental quality

ex: canary in coal mine, amphibiansex: canary in coal mine, amphibians

15. Species’ Roles in EcosystemsSpecies’ Roles in Ecosystems
 Keystone speciesKeystone species – have a large effect on the– have a large effect on the
types and abundances of other speciestypes and abundances of other species

can play critical roles in helping sustain ecosystemscan play critical roles in helping sustain ecosystems

Ex: pollinators, top predatorsEx: pollinators, top predators

loss leads to crash of other populationsloss leads to crash of other populations

16. Case Study: The American AlligatorCase Study: The American Alligator
 The American alligator:The American alligator:

largest reptile in North America, keystone specieslargest reptile in North America, keystone species
in its ecosystemsin its ecosystems

1930s – Hunted and poached1930s – Hunted and poached

1967 – added to the endangered species list1967 – added to the endangered species list

1977 – impressive comeback1977 – impressive comeback

more than a million alligators today in Floridamore than a million alligators today in Florida